Mechanical dotting device



May 25, 1937. B. L. SIMMONS I MECHANICAL DOTTING DEVICE Filed Sept. 15,; 1936 Patented May 25, 1937 UNITED STATES PATENT OFFICE 2 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3'70 0. G. 757) This application is made under the act of March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described and claimed may be manufactured and used by or for 5 the Government for governmental purposes without the payment to me of any royalty thereon.

My invention relates to improvements in devices for producing accurate work in drafting, and more particularly to improvements in that class of instruments known as dotters.

My invention differs from existing patents that employ an attachment on a ruling pen wherein the pen being drawn along the edge of a ruler or T square is lifted from the paper as the attachment passes over raised points ,on the surface of the straight edge thereby breaking the pens contact with the surface upon which the line is being ruled. Due to the extreme difficulty in always holding the pen exactly perpen- 20 dicular to the surface of the drawing, the exact length of the dots or dashes is problematical, it being possible to so slant the pen that it will be lifted entirely clear of the ruling surface and so produce no line, or slanted so that the attachment will pass over the lifting lugs without raising the pen and so produce an unbroken line. This fault is overcome in my invention by having the pen attached to a carriage which holds it rigidly in the proper position as the carriage is slipped along the base in a groove provided for this purpose.

My invention also differs from another patent which employs a wheel that rolls on the ruling surface, said wheel being geared to a wheel which in turning operates a cam attached to an arm carrying a ruling pen. As this complicated instrument is rolled on the drawing the pen is lifted from the paper as the cam is engaged. The greatest objection to this instrument is the possibility of the wheel in contact with the drawing surface slipping and thus producing a long dash where it is not wanted. I overcome this fault by having no frictional parts and no gears.

The objects of my invention are to provide a device of the character mentioned, simple in construction and cheaply made, while at the same time capable of producing accurate work and being conveniently operated.

These objects are attained by a simplified form of device, wherein a sliding carriage, equipped with a pen, is moved over a rack, thereby lifting the pen from the paper at predetermined intervals, as will hereinafter more fully be described.

Another object is to provide a means for holding a ruling pen at a predetermined angle while in use.

Another object is to provide a means for holding a barrel or cylinder type pen so that dotted lines wider than those obtainable by the use 5 of a ruling pen may be obtained.

Still another object of my invention is to provide a means for raising or lowering the pen with relation to the device and locking it in the predetermined adjustment, thereby permitting more than one type of broken line to be made with each spacer rack.

I attain the aforementioned objects, together with other objects readily apparent to those skilled in the art, by the construction illustrated in the accompanying drawing, in which- Figure'l is a perspective view of my device with a ruling pen in use therewith;

Figure 2 is an elevation view of my attachment for holding a barrel, or cylinder type pen point, shown with pen in place; while,

Figure 3 is a plan view of the same with the pen point removed;

Figures 4, 5, 6, 7, 8, 9, l0 and 11 are fragmentary elevation views of additional spacing racks with types of lines obtainable shown directly above them;

Figure 12 is a plan view of the bottom of carriage; and,

Figure 13 is a side elevation of carriage.

Similar numerals refer to similar parts throughout the several views.

Referring to the drawing, a ruler or base I, of either hardwood, bakelite, hard rubber, or other suitable material, has formed in its upper face a groove or slot 2, through which passes slide 3. Slide 3 is rigidly attached by screws (not shown) to a carriage 4. At point 5, the sides of carriage 4 become parallel and at right angles to the slide 3. The narrow end of the carriage is V shaped at the bearing point 6, where it contacts with the rack l5, as shown. A spring I is attached to the carriage 4, by means of a large headed, milled thumb screw 8. Screw 8 also acts as a handle for operating the carriage 4. Spring 1 is further held in place by the set screw 9, which releases or compresses the end of the spring I, and in so doing raises or lowers the pen I0, with relation to the carriage 4, and more particularly with relation to the bearing point 5 of the carriage 4. This provides a micrometer adjustment of the pen l0. Head H of screw 9 is marked with lines so that a desired setting may be established after changing to some other adjustment. A look nut I2 screws down against the carriage so as to lock the screw 9, in any adjustment desired. Further adjustment of the pen I0 may be had by loosening the screw I3, and sliding the pen up or down between the jaws I4. These jaws I4 are an integral part of the spring I, and have small grooves on their inside faces into which the blade of the ruling pen fits. The spacer racks I5, have formed thereon teeth I5. Spacer racks I5 are detachable and are adapted to fit snugly into groove IS on the base I and are secured in place at either end by two thumb nuts I! (only one shown), which screw down on a bolt (not shown) extending up through the base I and spacer rack I5. A slight V-groove I8, across the face of the spacer rack I5 provides a place where the bearing point 6 of the carriage l may be rested with the point of the pen I El 011 the paper while the device is moved to another position. A groove I8 should be made in each end of all racks I5. The edge I9, of the base I is shaped as shown to facilitate its use as a straight edge or ruler, the lower side being beveled upwardly to lessen the possibility of ink running thereunder and blotting on the drawing. Samples of lines 29, which may be drawn with my device are shown in Figures 4-11. These are shown with relation to the particular spacing racks I 5 which produce them. Figures 611 show more than one type of line 20, which may be secured with a single rack of the type shown by raising or lowering the pen ID by means of the screw II. Figures 2 and 3 show a spring I, the end of which is adapted to hold a barrel or cylinder type pen IE). A small spring 2I, reinforces the jaws 22, of spring I. Jaws 22 are of a different type than the jaws I4. The jaws I4 and 22 in each case are an integral part of the spring I, the entire unit being formed from a single piece of steel.

In operation, the rack I5, having been selected which produces the type of line desired, is fastened in the groove IS, on the base I, by means of the two nuts IL. The base I is then placed on the surface of the drawing, the edge 19 being parallel to the position in which it is desirable to rule a broken line and distant therefrom a distance equal to the distance of the pen point from the edge I9, this is easily ascertained by trial.

With the carriage 4, in place upon the base I, the pen I 0 is adjusted by using the screw II,

until the desired length of dots or dashes is obtained. It is then secured in said adjustment by tightening the lock nut I 2.

Lifting the carriage 4, clear of the base I, the pen is filled with ink, as a ruling pen is filled. Grasping the screw 8, by the thumb and fingers of one hand the slide 3, is placed in the groove 2, of the base I, and the point of the pen It] is lowered to the surface of the drawing. With a slight pressure on screw 8, the carriage l is now slid along the base I. As the point 6 of the carriage 4 passes over the teeth I5, or raised portions of the rack I5, the end of the carriage 4 is raised thereby lifting the point of the pen ID from the paper and producing a break in the line.

By depressing the end of the spring I by means of screw 'II, the point 6 of the carriage 4 will be raised, so that it will entirely clear the raised portions of the rack I5, and thus produce an unbroken line.

It is quite apparent that with racks I5 (Figures 7-11), by the manipulation of the screw II, the point 6 of carriage 4, may be made to entirely clear the lower of the raised portions or teeth I5 on the rack I5, while tripping over the higher ones. Thus broken lines or entirely different character may be ruled with one rack.

Having thus described my invention, what I claim for Letters Patent is:

l. A dotting device, comprising in combination 5-7.

a ruler with a V shaped carriage, having a bearing point formed thereon, a slide attached to said carriage and adapted to engage a groove formed in said ruler, a spr ng mounted on said carriage and having jaws formed thereon, holding scribing means, a scribing means, means for adjusting said scribing means on said carriage, and a spacer rack mounted on said ruler in position to cooperate with said carriage.

2. A dotting device, comprising in combination adapted for 5' 

